Based on information that tumor cells contain abnormal quantities of glyceryl ether phospholipids, it is likely that the outer membrane of tumor cells also contain abnormal quantities of glyceryl ethers, a specific change which would make it important to determine if this alteration might be related to changes in properties such as loss of contact inhibition and changes in adhesive qualities in tumors. Accordingly, we propose to study the O-alkyl lipid composition of outer membranes in a variety of tumors, and in normal cells and to study the rate of turnover of O-alkyl lipids by means of the labeled precursors, (1,3-C14) dihydroxyacetone phosphate and (1-C14) hexadecanol. Specifically, we propose to examine the following questions. First, how much and what kind of glyceryl ether can be found in the external membrane in normal and neoplastic cells? Second, is there a difference in the amount of glyceryl ether found in solid versus non solid tumors in the rapidly growing versus slowly growing normal cells? Third, is there a correlation between the presence of glyceryl ether in membranes and the degree of loss of contact inhibition? We propose to continue ongoing studies on the biosynthesis of alkyl ethers of glycerol in Ehrlich ascites tumor cells. In the past year we have published data showing that there is a hydrogen exchange involving acyl dihydroxyacetone phosphate in the pathway leading to the formation of O-alkyl dihydroxyacetone phosphate. The data strongly suggest the formation of another intermediate. Our immediate specific aims in this area are: 1) to determine if tritiated glyceryl ethers are formed from acyl DHAP in the presence of tritiated water, and to identify and detect a suspected new intermediate in O-alkyl lipid synthesis. We also propose to continue recently begun studies on free fatty alcohol transport tissue uptake and interconversion.